Various arrangements have heretofore been proposed for aligning, supporting and rotating hollow tank sections during welding of the sections in end-to-end abutting relation to form an elongated tank. Such arrangements however are not adapted to accommodate and rotate scalene frusto-conical tank sections, such as used to form sloped bottom tanks.
One such arrangement is illustrated in U. S. Pat. No. 3,888,103, issued June 10, 1975. In this arrangement a plurality of hydraulic clamping jacks arranged in circular configuration are used to form and support the edges of cylindrical tank sections for welding in end-to-end abutting relation. Vertically adjustable rollers position on each side of the hydraulic jacks support the lower surfaces of the tank sections for rotation. The hydraulic jacks are mounted on a fixed support and cannot however be rotated with the tank sections and the tank sections must be first tack welded and the hydraulic jacks retracted before the tank sections can be rotated to complete the welding. Because the tank sections are supported only at the lower surfaces by the adjustable rollers, scalene frusto-conical tank sections cannot be accommodated for rotation as the axes of scalene frusto-conical sections do not coincide with the axis of the circular abutting edges of the tank sections.
Another arrangement is shown in the April, 1969 issue of the publication "Welding and Metal Fabrication." In this arrangement a pair of segmental sizing rings are used to clamp and hold the edges of cylindrical tank sections in end-to-end, abutting relation during welding. The sizing rings are rotably mounted and rotate with the tank sections during welding. The sizing rings however will only accommodate tank sections of a single diameter, and different sizing rings must be used for different diameter tank sections. Also the tank sections are supported on each side of the sizing rings by rollers which engage only the lower surfaces of the tank sections and scalene frusto-conical tank sections cannot be accommodated for rotation as the axes of the frusto-conical sections do not coincide with the axis of the circular abutting edges of the tank sections.